PARIS, July 18 (Reuters) - Financial bookmakers expect to see the leading European benchmark indexes fall on Monday, adding to last week's sharp losses, as results from the region's bank stress tests fail to dispel investors' concerns. Financial spreadbetters expected Britain's FTSE 100 to open around 26 points lower, or down 0.4 percent, Germany's DAX to open 28 points lower, or down 0.4 percent, and France's CAC-40 to open 25 points lower, or 0.7 per